The present invention relates to a spray nozzle for an irrigation apparatus.
Spray nozzles for use with pivot type irrigation machines, tractor spray bars, and similar devices are commonly made of brass, which is corrosion-resistant and easily machined. A problem commonly associated with such nozzles is that they are quickly eroded by the flow of irrigation water, particuarly if the water has a high abrasive content as is the case in many agricultural environments. In some instances, an orifice where water is emitted from the nozzle or a deflector surface that determines the spray pattern of the nozzle can be worn, after a single day of use, to the extent that the spray pattern of the nozzle is substantially altered and its efficiency is greatly reduced. Other materials that have been proposed as substitutes for brass in the construction of spray nozzles have proven unsatisfactory, however, and brass nozzles continue to be the industry standard.
Another problem associated with presently known spray nozzles is that they are generally capable of producing only one spray pattern, assuming a given water supply pressure. It is sometimes desired to change this pattern to accommodate a different arrangement of crops, changes of season, or climatic variations. This traditionally necessitates replacement of the relatively expensive brass spray nozzles. It has also been found that spray nozzles of traditional design produce an unequal lateral distribution of water, the heaviest concentrations being at the edges of the pattern.
A principal object of the present invention is to overcome the problems of erosion usually associated with spray nozzles, provide a more uniform lateral distribution of water within the spray pattern, and at the same time provide a nozzle that readily permits modification of its spray pattern.